From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gavin Flower Subject: Re: Best way to create RAID-6 for swap partition - existing one failed Date: Wed, 18 May 2011 13:13:15 -0700 (PDT) Message-ID: <986071.90796.qm@web65108.mail.ac2.yahoo.com> References: <4DD41713.5070407@hardwarefreak.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <4DD41713.5070407@hardwarefreak.com> Sender: linux-raid-owner@vger.kernel.org To: Stan Hoeppner Cc: linux-raid@vger.kernel.org, neilb@suse.de, mb@gem.win.co.nz List-Id: linux-raid.ids --- On Thu, 19/5/11, Stan Hoeppner wrote: > From: Stan Hoeppner > Subject: Re: Best way to create RAID-6 for swap partition - existing = one failed > To: "Gavin Flower" > Cc: linux-raid@vger.kernel.org, neilb@suse.de, mb@gem.win.co.nz > Date: Thursday, 19 May, 2011, 6:59 > On 5/16/2011 4:41 PM, Gavin Flower > wrote: >=20 > > Motivation, existing RAID-6 swap partition > failed.=A0 I am thinking I should recreate it in a new > format, as currently it is 'Version : 0.90', rather than > simply rebuild it. > >=20 > Forget using a partition.=A0 Simply use a swap > file.=A0 This example creates > a 1GB swap file in the / filesystem.=A0 You can locate > it on any > filesystem you wish. >=20 > # swappoff -a > # dd if=3D/dev/zero of=3D/swapfile1 bs=3D1024 count=3D1048576 > # mkswap /swapfile1 > # swapon /swapfile1 > # vi /etc/fstab > Add: > /swapfile1 swap swap defaults 0 0 >=20 > and remove your old entry for the failed swap partition. >=20 > There is little performance difference between swap files > and swap > partitions with modern kernels.=A0 The kernel will map > the disk location > of the swap file and perform direct disk access, bypassing > the > filesystem and buffer cache. >=20 > --=20 > Stan >=20 Thanks. Interesting! (Reminds me of when I first got into Linux. Then you could have any si= ze swap file up to 128 MB, and have up to 8 swap files, for a maximum o= f 1 GB. I then had about 64 MB of RAM - now I have 8 GB of RAM. Also, s= wap partitions were recommended. When the 2.4 kernel first came out, i= t was said to be faster if you had at least 16 MB.) I read up and could not see any benefit in changing, so I ended up 'sim= ply' reassembling the partition. The 2 things I had thought of altering, were the version of the super b= lock and the chunk size. With the amount of RAM I have, performance is = not normally an issue, I was thinking of reliability. The badblocks ru= n did not reveal any problems, nor did checking the smart diagnostics i= n detail reveal anything significant. I think it was some kind of kern= el error, transient anyhow. SUGGESTION: Could we please have some explanation of the benefits and tradeoffs bet= ween the different values of things like chunk size and super block ver= sion. -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html